local module = {};

--[[
this feature allows get object without making some created callback and local var
but, it can't allows mulit id and object
this feature should be upgraded
]]
local wrap = coroutine.wrap;
local insert = table.insert;
local remove = table.remove;
local gmatch = string.gmatch;
local gsub = string.gsub;

local function catch(...)
	local passed,err = pcall(...);
	if not passed then
		warn ("[QUAD] Error occured while operating async task\n" .. tostring(err));
	end
end

local week = {__mode = "v"};

---@param shared quad_export
---@return quad_module_store
function module.init(shared)
	---@class quad_module_store
	local new = {__type = "quad_module_store"};
	local items = shared.items;

	-- id space (array of object)
	local objectListClass = {__type = "quad_objectlist"};
	function objectListClass:each(func)
		local index = 1;
		for i,v in pairs(self) do
			wrap(catch)(func,index,v);
			index = index + 1;
		end
	end
	function objectListClass:eachSync(func)
		local index = 1;
		for _,v in pairs(self) do
			local ret = func(index,v);
			index = index + 1;
			if ret then
				break;
			end
		end
	end
	function objectListClass:remove(indexOrItem)
		local thisType = type(indexOrItem);
		if thisType == "number" then
			remove(self,indexOrItem);
		else
			for i,v in pairs(self) do
				if v == indexOrItem then
					remove(self,i);
					break;
				end
			end
		end
	end
	function objectListClass:isEmpty()
		if next(self) then return true; end
		return false;
	end
	function objectListClass.__new()
		return setmetatable({},objectListClass);
	end
	function objectListClass:__newIndex(key,value) -- props setter
		self:each(function (this)
			this[key] = value;
		end);
	end
	objectListClass.__mode = "kv"; -- week link for gc
	objectListClass.__index = objectListClass;

	-- get object array with id (objSpace)
	function new.getObjects(id)
		local list = items[id];
		if list then return list; end
		list = objectListClass.__new(id);
		items[id] = list;
		return list;
	end
	-- get first object with id (not array)
	function new.getObject(id)
		local item = items[id];
		return item and item[next(item)];
	end
	--TODO: if item is exist already, ignore this call
	-- adding object with id
	function new.addObject(ids,object)
		for id in gmatch(ids,"[^,]+") do -- split by ,
			-- remove trailing, heading spaces
			id = gsub(gsub(id,"^ +","")," +$","");
			local array = items[id];
			if not array then
				array = objectListClass.__new();
				items[id] = array;
			end
			insert(array, object);
		end
	end

	local registerClass = {
		__type = "quad_register";
		register = function (s,efunc)
			local self = s.store;
			local events = self.__evt;
			for key in s.key:gmatch("[^,]+") do
				key = key:gsub("^ +",""):gsub(" +$","");
				local event = events[key];
				if not event then
					event = setmetatable({},week);
					events[key] = event;
				end
				insert(event,efunc);
			end
		end;
		with = function (s,wfunc)
			-- s.wfunc = wfunc;
			-- return s;
			return setmetatable({wfunc = wfunc},{__index = s});
		end;
		default = function (s,dvalue)
			-- s.dvalue = dvalue;
			-- return s;
			return setmetatable({dvalue = dvalue},{__index = s});
		end;
		tween = function (s,tvalue)
			-- s.tvalue = tvalue;
			-- return s;
			return setmetatable({tvalue = tvalue},{__index = s});
		end;
		---@deprecated
		from = function (s,fvalue)
			warn "[QUAD] register:from() is deprecated. You can use register:add(t:table|function) instead";
			-- s.fvalue = fvalue;
			-- return s;
			return setmetatable({fvalue = fvalue},{__index = s});
		end;
		add = function (s,avalue)
			-- s.avalue = avalue;
			-- return s;
			return setmetatable({avalue = avalue},{__index = s});
		end;
		-- return init data
		calcWithDefault = function (s,withItem)
			local with = s.wfunc;
			local tstore = s.store;
			local rawKey = s.key;
			local tween = s.tvalue or s.dtvalue;
			local from = s.fvalue;
			local add = s.avalue;
			local set = tstore[rawKey];
			if set ~= nil or (rawKey:match(",") and with) then
				if add then
					set = set + add;
				end
				if from then
					set = from[set];
				end
				if with then
					set = with(tstore,set,rawKey,withItem);
				end
				return set,tween;
			else
				local dset = s.dvalue;
				if dset ~= nil then
					return dset,tween;
				end
				warn "[Quad] no default value found.";
			end
		end;
		calcWithNewValue = function(s,withItem,newValue,key)
			local with = s.wfunc;
			local tstore = s.store;
			local tween = s.tvalue or s.dtvalue;
			local from = s.fvalue;
			local add = s.avalue;
			if add then
				newValue = newValue + add;
			end
			if from then
				newValue = from[newValue];
			end
			if with then
				newValue = with(tstore,newValue,key,withItem);
			end
			return newValue,tween;
		end
	};
	registerClass.__index = registerClass;

	-- bindable store object
	local store = {__type = "quad_store"};
	local storeIdSpace = {};
	function store:__index(key)
		local this = self.__self[key];
		if this ~= nil then
			return this;
		end
		return store[key];
	end
	function store:__newindex(key,value)
		-- if got register, just copy data to self and connect
		if type(value) == "table" and value.__type == "quad_register" then
			warn "[Quad] adding register value on store is only allowed when init store. set value request was ignored";
			return;
		end
		self.__self[key] = value;
		local event = self.__evt[key];
		if event then
			for _,v in pairs(event) do -- NO ipairs here
				wrap(catch)(v,store,value,key);
			end
		end
	end
	-- init bindings
	function new.__initStoreRegisterBinding(self,withItem)
		local selfTweens = self.__tweens;
		local selfValues = self.__self;
		for key,item in pairs(selfValues) do
			if type(item) == "table" and item.__type == "quad_register" then
				-- fetch data from origin
				do
					local tstore = item.store;
					for tkey in item.key:gmatch("^[,]") do
						selfValues[tkey] = tstore[tkey];
					end
				end

				-- calc value
				do
					local setValue,tween = item:calcWithDefault(withItem);
					selfValues[key] = setValue;
					selfTweens[key] = tween;
				end

				-- make event connection
				item:register(function (_,newValue,eventKey)
					-- !HOLD IT SELF TO PREVENT THIS REGISTER BEGIN REMOVED FROM MEMORY
					local setValue = item:calcWithNewValue(withItem,newValue,eventKey);
					self[key] = setValue;
				end);
			end
		end
	end
	-- create register
	function store:__call(key,func)
		local last = self.__self[key];
		if last and type(last) == "table" and getmetatable(last) == registerClass then
			return last;
		end
		local register = self.__reg[key];
		local tweens = self.__tweens;
		if not register then
			register = setmetatable({
				key = key;
				store = self;
				dtvalue = tweens and tweens[key];
			},registerClass);
			self.__reg[key] = register;
		end

		if func then
			register.register(func);
		end
		return register;
	end
	function store:default(key,value)
		local old = self[key];
		if old == nil then
			self[key] = value;
			return;
		end
	end
	function new.new(self,id)
		local this = setmetatable(
			{
				__self = self or {}, -- real value storage
				__evt = {}, -- changed event handler functions (dict of array)
				__reg = setmetatable({},week), -- save registers
				__tweens = {} -- tweens (if inited with register, save tween and use as default tween data)
			},store
		);
		if id then -- save in id space
			storeIdSpace[id] = this;
		end
		return this;
	end
	local storeNew = new.new;
	function new.getStore(id)
		return storeIdSpace[id] or storeNew({},id);
	end

	return new;
end

return module;